There is no particularly clever way of doing it. Just move your tanks forward a little at the time, say, 10 meters forward on each move order. And keep a little distance between your two tanks. There is one or two enemy tanks (I forget how many) but your tanks should be able to deal with them on their own. Your main job is to kill the RPG gunners on the rooftops, and here the sniper rifle comes in very handy.